def fibonacci(num):
    if num == 1 or num == 2:
        return 1
    return fibonacci(num - 1) + fibonacci(num - 2)


def main():
    try:
        num = int(input('请输入一个整数：'))
    except ValueError:
        print('请输入一个整数！')
    print('斐波那契数列中的第 {} 个数为：{}'.format(num, fibonacci(num)))


main()
